There has been well-known a sliding bearing including a center portion and end portions on a bearing surface, wherein a convexo-concave portion is formed in at least one of the center portion and the end portions (Patent Literature 1).
For example, FIG. 4 of Patent Literature 1 discloses a sliding bearing in which groove-like convexo-concave portions extending along the circumferential direction are respectively formed in a center portion and an end portion of a cylindrical bearing surface and a pitch in the center portion is set smaller than a pitch in the end portion.
FIG. 9 of Patent Literature 1 discloses a sliding bearing in which a groove-like convexo-concave portion extending along the circumferential direction is formed in an end portion of a cylindrical bearing surface but is not formed in a center portion and the surface of the center portion is formed flat.
Further, FIG. 11(a) of Patent Literature 1 discloses a sliding bearing in which groove-like convexo-concave portions extending along the circumferential direction are respectively formed in a center portion and an end portion of a cylindrical bearing surface and the depth of grooves in the end portion is set larger than the depth of grooves in the center portion.